NO. 1 HARTMAN : POLYCHAETOUS ANNELIDS 49 



The fourth parapodium (pi, 1, fig. 4) has 5 yellow acicula that taper 

 distally to blunt straight rods, and 9 or 10 shorter limbate setae inferiorly. 

 The acicula are slenderer than those farther back. A fifteenth parapodium 

 is provided with the following setal structures: 3 heavy yellow acicula 

 that are rodlike but taper distally, many smooth simple limbate setae in 

 the upper and middle parts of the fascicle, and a stout, subacicular, bi- 

 dentate hook (pi. 1, fig, 6), together with 5 composite spinigers (pi. 1, 

 fig. 5) below. In the sixteenth to twentieth parapodium the arrangement 

 is similar, but the composite spinigers are replaced by a second subacicular 

 hook (pi, 1, fig, 7) and there are only 2, instead of 3, yellow acicula. 

 Composite spinigers occur in the fourth to fifteenth parapodium, in a 

 ventral position of the fascicle. Pectinate setae (pi, 1, fig, 8), nowhere 

 conspicuous, are present from the sixteenth setiger to the ends of the 

 pieces. 



The proboscidial armature, not originally described, is typically onu- 

 phid, both mandibles and maxillae well developed. The mandibles are 

 hard, calcareous, with sharp, white, cutting edges, and have long basal 

 rods that are separated for most of their length (pi. 1, fig. 2). The max- 

 illae have carriers that are longer than broad and basally rounded (pi. 1, 

 fig. 1 ) ; the forceps are falcate. On the left side the maxillary pieces have, 

 from the second to fourth piece, 7, 7, and 8 teeth, respectively; the fifth is 

 a flat, edentate plate. On the right side, the second piece has 7 teeth and 

 the third has 9 teeth; the fifth piece resembles the corrsponding one on the 

 left side (pi, 1, fig, 1). 



The tube is tough, parchmentlike, covered with debris and gravel. 



Distribution. — Based on these collections, R. longisetosum occurs ex- 

 tensively off southern California, south at least to Cedros Island, Mexico, 

 and the Galapagos Islands, in depths ranging from 10 to 400 fms. It is 

 usually associated with sandy or muddy bottoms. 



Genus DIOPATRA Audouin and Edwards 

 Type D. cuprea (Bosc) 



Diopatra has many characters common to Onuphis (below), but is 

 most clearly distinguished in having spiraled branchiae on some anterior 

 segments. The prostomium is similarly provided with a pair of short, 

 frontal antennae and 5 long, occipital tentacles, with longer or shorter 

 annulated ceratophores. In addition, there is usually a pair of clear, cir- 

 cular areas posterior to the insertion of the inner lateral tentacles, which 

 incorrectly have been called eyes; they are pale, translucent, probably 

 sensory organs. The first ring or segment, sometimes designated peri- 



